Thursday, 7 November 2013
SCIENCE FAIR PROJECT - FISH - By Rafael Marcos
Fish are vertebrates aquatic animals,generally poikilotherms, most of them are covered with scales and have fins, that permit them to move in the water and gills, which trap the oxygen in the water.
Fish are found in salt and in fresh water, for example the gudgeon, that lives in rivers in the mountains, and they also live in the deep ocean, like gulper eels.
When salmon appeared on Earth isn’t known for sure; however the information that exists permits scientists to know that “Teleosts ” the group of fish which salmon belong to, dominated the water in the Cretaceous period that started 135 millions years ago. At the same time dinosaurs and other giants animals inhabited the Earth and even the oldest ancestors of humans appeared.
The life cycle of a salmon:
The salmons are born from eggs and live in the river. After some time they go to the sea and when they become adults, they go back to the river to lay more eggs. The female lays the eggs and the male fertilizes them. Once they lay their eggs, they die.
MORE EXAMPLES OF FISH
The Hippocampus histrix is a type of sea horse they generally live in the sea , they come from the Indian oceanic but we can find them too in the
or the Arabic sea. The
Hippocampus histrix can be 15 cm in the adult age. Its body is S shaped, like
most sea horses. Read
The yellow tail lady
The yellow tail lady originated in the coral reef of the
ocean. They can grow upto 15 cm. They are a blue electronic colour
with a yellow tail. Their body shape is long and flattened, like most of
El hypanicistrus zebra
The Hypancistrus zebra is from
Brazil, from the river Xingu.
They can be from 5 to 10 cm long. Their body is flat and long, they’ve got a
My experiment also showed the internal and external features of fish. For this I placed a sea bass on a tray. I indicated the external features like scales, fins, lateral line, operculum, eyes, mouth etc. With some tweezers I opened the operculum to see the gills. The gills are very red because they are full of capillaries with blood, ready to trap the oxygen.
I also prepared a fish tank with fish and aquatic plants to indicate the natural gas exchange between them both producing a balance in the ecosystem.
Watch this video of our fish tank!
· Revista national geographic (de mi casa) : el mundo debajo del agua